Actually, don’t waste time in general.

Or perhaps don't waste time without purpose? Also, it depends on what one considers a "waste of time." A hiking picnic in an idyllic meadow may be worth the time and effort to some, but perhaps not to others. I personally prioritize time with friends and family over other pursuits simply because some of the top complaints people have on their death beds are "worked too much" and "didnt spend enough time with friends/family." However, society doesn't necessarily reward us for prioritizing those, either.

Anyway, as long as you get value out of what you are doing, it is not time wasted.